Diff drive and odometry

#diff_drive   #odom   #odometry   #ros2   #ignition  

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Table of Content

LAB

• Add diff drive plugin
• publish odometry, odometry tf and cmd_vel from ignition to ros2 using bridge

Note

check joint state post for project structure and files

Note

Install rqt_robotic_steering for GUI cmd_vel control

sudo apt install ros-humble-rqt-robot-steering

bridge

ign topic --list
#
/clock
/gazebo/resource_paths
/gui/camera/pose
/model/basic_mobile_bot/cmd_vel
/model/basic_mobile_bot/odometry
/model/basic_mobile_bot/tf
/stats
/world/demo/clock
/world/demo/dynamic_pose/info
/world/demo/model/basic_mobile_bot/joint_state
/world/demo/pose/info
/world/demo/scene/deletion
/world/demo/scene/info
/world/demo/state
/world/demo/stats

- bridge cmd_vel (/model/basic_mobile_bot/cmd_vel) - bridge odometry (/model/basic_mobile_bot/odometry) - bridge tf (/model/basic_mobile_bot/tf)

# cmd_vel bridge 
    cmd_vel_bridge = Node(package='ros_gz_bridge', executable='parameter_bridge',
            namespace = namespace,
            name = 'cmd_vel_bridge',
            output='screen',
            parameters=[{
                'use_sim_time': use_sim_time
            }],
            arguments = [
                ign_model_prefix + '/cmd_vel' + '@geometry_msgs/msg/Twist' + ']ignition.msgs.Twist'
            ],
            remappings = [
                (ign_model_prefix + '/cmd_vel', '/cmd_vel')
            ])

    # odometry bridge 
    odometry_bridge = Node(package='ros_gz_bridge', executable='parameter_bridge',
            namespace = namespace,
            name = 'odometry_bridge',
            output='screen',
            parameters=[{
                'use_sim_time': use_sim_time
            }],
            arguments = [
                    ign_model_prefix + '/odometry' + '@nav_msgs/msg/Odometry' + '[ignition.msgs.Odometry'
            ],
            remappings = [
                (ign_model_prefix + '/odometry', '/odom')
            ])

    # odom to base_link transform bridge
    odom_base_tf_bridge = Node(package='ros_gz_bridge', executable='parameter_bridge',
            namespace = namespace,
            name = 'odom_base_tf_bridge',
            output = 'screen',
            parameters=[{
            'use_sim_time': use_sim_time
            }],
            arguments = [
                ign_model_prefix + '/tf' + '@tf2_msgs/msg/TFMessage' + '[ignition.msgs.Pose_V'
            ],
            remappings = [
                (ign_model_prefix + '/tf', '/tf')
            ])

get bridge source

tf